IP Multimedia Subsystem (IMS) as standardized by 3rd Generation Partnership Program (3GPP) Technical Specification (TS) 23.228 V8.7.0 (2008-12) and related 3GPP specifications can be denoted as an architectural framework for delivering internet protocol (IP) multimedia services. By IMS, it is possible to provide “Internet services” over GPRS, Wireless LAN, CDMA2000,fixed line, etc. To ease the integration with the Internet, IMS may use Internet protocols wherever possible, for instance Session Initiation Protocol (SIP). IMS intends to aid the access of multimedia applications from wireless and wired terminals. A user operating an IMS terminal (such as mobile phones, personal digital assistants (PDAs) and computers, also known as IMS user equipment) can register directly on an IMS network.
A user profile associated to an IMS user may be stored on a Home Subscriber Server (HSS) including one or more Filter Criteria (FC) used when determining which Application Server (AS) is invoked for the IMS user.
In the context of this application, the term “user equipment” may particularly denote communication devices to be operated by a user and to be coupled to a communication network. Examples are mobile phones, laptops or personal computers, data cards for plugging or on-board integration into laptops or personal computers, personal digital assistants (PDAs), navigation systems, etc. Hence, mobile (for example portable) or stationary communication devices can be operated in accordance with an IMS architecture. For instance, such a communication device may be used in the context of telecommunications.
The term “application provider” may particularly denote an entity having the capability to provide an assigned application or service to a user equipment. Such an application provider may comprise an application server to be communicatively coupled in a communication network. Examples for an application provider are a Session Initiation Protocol Application Server (SIP-AS), an Internet Protocol Multimedia Service Switching Function (IM-SSF), an Open Services Architecture Service Capability Server (OSA-SCS), or a Service Capability Interaction Manager (SLIM).
The term “application” may particularly denote a specific service, particularly a multimedia or telecommunications service, which can be provided by an application provided to a user equipment.
The term “service point trigger” (SPT) may particularly denote one or more points in an SIP signaling that may cause a control device such as a S-CSCF (Serving Call Session Control Function) to send or proxy the SIP message to an SIP-AS, OSA-SCS, IM-SSF or another application provider. The subset of all possible SPTs which are relevant to a particular application may be defined by means of one or more filter criterion.
The term “filter criterion” may particularly denote information which the S-CSCF receives from the HSS or an AS that may define the relevant SPTs for a particular application. They may define the subset of SIP requests received by the S-CSCF that should be sent or proxied to a particular application. More particularly, an Initial Filter Criterion (iFC) may be denoted as a filter criterion which may be stored in the HSS as part of a user profile and downloaded to the S-CSCF upon user registration. They may represent a provisioned subscription of a user to an application.
FIG. 2 illustrates an architecture 200 for service provision for an IP Multimedia Subsystem. Hence, the functional architecture for support of service provision for an IP multimedia subsystem can be seen in FIG. 2.
FIG. 2 illustrates the architecture with an S-CSCF 250 communicating to HSS 260 via a Cx interface and communicating to various Application Servers via an IP multimedia service control (ISC) interface. The Application Servers can be:                SIP Application Servers 208 which may host and execute services. It may be intended to allow the SIP Application Server 208 to influence and impact the SIP session on behalf of the services;        IM-SSF 204 which is a particular type of application server the purpose of which is to host the Customised Applications for Mobile networks Enhanced Logic (CAMEL) network features (i.e. trigger detection points, CAMEL Service Switching Finite State Machine, etc) and to interface to CAP as specified in 3GPP TS 29.078;        OSA service capability server 206 which interfaces to the OSA framework Application Server 210 and which provides a standardized way for third party secure access to the IM subsystem. The OSA reference architecture defines an OSA Application Server 210 as an entity that provides the service logic execution environment for client applications using the OSA API as specified in 3GPP TS 29.198. This definition of Application Server differs from the definition of Application Server in the context of service provisioning for the IM subsystem, i.e. the entity communicating to the S-CSCF 250 via the ISC interface;        in addition a specialized type of SIP Application Server, the service capability interaction manager (SCIM) 202 which performs the role of interaction management between other application servers.        
All the Application Servers, (including the IM-SSF 204 and the OSA-SCS 206) behave as SIP application servers on the ISC interface. In addition the Application Servers can also interact with an MRFC (Media Resource Function) 270 via the S-CSCF 250 (ISC and Mr interfaces) in order to control Multimedia Resource Function processing.
Moreover, a Camel Service Environment unit 212 is shown.
The implementation of Filter Criteria as a basis for a trigger mechanism for triggering specific communication paths or the provisioning of specific services is already possible with the conventional architecture of FIG. 2.
However, conventional IMS architectures may have the shortcoming that it may be difficult or even impossible to ensure that an application is provided to a user equipment with a multimedia content which fits specifically and accurately to user's needs in view of the actual operation conditions of the user equipment.